Temperature control in refrigerating or cooling apparatus



P 2, 1939 J. F. B. \VIIDAL 2,172,916

TEMPERATURE CONTROL IN REFRIGEFATING OR COOLING APPARATUS Filed April21, 1938 3 Sheets-Sheet 1 MIME/V701? haam M4,. I

Sept; 12, 1939. J. F. B. VIDAL TEMPERATURE CONTROL IN REFRIGERATING ORCOOLING APPARATUS '3 Sheets-Sheet 2 Filed April 21, 1938' m ME j gun.

J. F. B. VIDAL Sept. 12, 1939.

TEMPERATURE CONTROL IN REFRIGERATING OR COOLING APPARATUS Filed April21,- 1938 5 Shets-Sheet 5 Patented Sept. 12, 1939 PATENT OFFICETEMPERATURE CONTROL IN REFRIGER- ATING OR COOLING APPARATUS John FurseBancroft Vidal, Purle Stone & Company,

signor to J.

ford, England, a company of Application April 21,

In Great Britain April 22,

4 Claims.

This invention comprises improvements in and connected with temperaturecontrol in refrigerating or cooling apparatus and particularly inrefrigerator chambers adapted for use in vehicles, railway carriages,vans and the like.

The principal object of the present invention is to improveautomatically controlled refrigerator installations which areself-contained and which dispense with the employment of any outside orauxiliary power means for the operation of the control devices.

In these installations a refrigerant container is arranged in a heavilyinsulated box or chamber having controlled communication with the coldstorage space, .such communication being regulated or shut-off byshutters, doors or other valve-like means. The partial or completeclosing of such shutters has the efiect of reducing or stopping thecirculation of relatively warm air from the cold storage chamber pastthe refrigerant container, thereby slowing down or arresting theevaporation of the refrigerant.

Apparatus for temperature control according to this invention comprisesa container for vaporizable refrigerant and adapted for withstandingpressure, a diaphragm or bellows device adapted for being flexed" bypressure admitted from the container, temperature-responsive meansoperative for controlling pressure admission to the diaphragm or bellowsdevice, and a shutter device operatively connected with the diaphragm orbellows and effective for regulating air circulation past the container.

In order to enable the invention to be readily understood reference ismade to the accompanying drawings, wherein:

Figure 1 is a more or less diagrammatic cross sectional view of avehicle body fitted with one example of refrigerating apparatus inaccordance with these improvements.

Figure 2 is a diagrammatic representation of another example.

Figure 3 is a longitudinal sectional elevation of the roof of a railwayvehicle fitted with re- 45 frigerating apparatus similar to that seen inFigure 2.

Figure 4 is a cross section of Figure 3.

Figure 5 is a sectional elevation to a larger scale of the pressuredevice and linkage seen in Figure 3.

Referring to Figure l, a represents a cold storage chamber or insulatedvehicle body and b a heavily insulated compartment atone side or end ofsuch chamber or body. The compartment b has a relatively large openingat the bot- England, as- Limited, Dept- Great Britain 1938, Serial No.203,428

tom communicating with the cold storage chamber a and in this openingare fitted louvre shutters c or other suitable doors or valves. Thecompartment b also has a relatively small opening d at the topcommunicating with the top 5 space of the cold storage chamber a. Withinthe chamber b is suitably supported a C02 container e which ispreferably provided with heat exchange fins or the like and ishermetically closed and adapted for sures. It is provided with ablow-off valve 1' which may be adjusted to limit the pressure in thecontainer e say to about five pounds per square inch. A gas pipe 9 isled from the container to a heat exchange device h, such as a 15 coil,disposed externally of the cold storage chamber a and serving as apre-heater. From the coil h a gas pipe 9' passes to a suitable powerelement which may take the form of an expansibie diaphragm or bellowsdevice 7a which is appropriately linked with the louvre shutters c foroperating the latter. In the pipe I there is a. valve at l in operativeconnection with a thermostat m disposed within the cold storage chambera; The thermostat m may be a bulb containing a suitable fluid and thevalve at I may be a needle valve operatively connected with a diaphragmor piston under the influence of pressure changes due to expansion andcontraction of the fluid in the bulb m. The diaphragm device k is fittedwith a restricted leakage vent which may take the form of a small tubefitted with a valve k the last named being adjusted to permit of asuitable rate of pressure leakage from the diaphragm chamber.

The operation will now be apparent. The storage chamber a having beenclosed after the introduction of goods, air will circulate through thecold compartment b, the warm air from the chamber a entering at d anddescending, upon 40 being cooled by the CO2 container e, so that anoutflow of cold air from b to a past the open louvres c is effected. Theheat exchange between such air and the container e causes evaporation ofthe CO2 so that a pressure is developed within the container, suchpressure being limited by the blow-ofi valve I. When the circulation ofcold air has reduced the temperature within the storage chamber a to thedesired degree, the thermostat m produces an opening of the valve at Iso that pressure gas passes to the power element is which thereuponoperates to move the shutters 0 towards the closed position, therebythrottling the circulation and reducing the rate of evaporation in thecontainer e. The

withstanding low presvalve 1 and power element It cannot be hindered inoperation by freezing or condensation, because the gas has been warmedin the preheater coil 71. before passing to them. When the temperaturehas been reduced to a value within the prescribed limits, the thermostat122. may produce a complete closure of the shutters 0 so thatcirculation of cold air and evaporation of CO2 are arrested. In thiscondition, the top opening d may permit of a little spillage of cold airfrom time to time from the compartment b into the chamber a. Reverseaction of the thermostat may operate to shut off the flow of gas to thepressure device 10 and to relieve the pressure therein. However, in theexample illustrated in Figure 1, the leakage at whilst slow enough tomaintain an operating pressure in the device It during operation of thelatter, is suflicient for exhausting the space behind the diaphragm inreasonable time when the valve at Z is closed by the thermostat. In theforegoing it has been assumed that the shutters c are self-opening, asby providing them with spring or gravity means for that purpose, andthat pressure is admitted to the device It for closing them. However,the shutters 0 might equally be self closing and the pressure admittedto the device It for opening them.

The modified arrangement in Figure 2 difl'ers from that in Figure 1principally in regard to the shutter devices. In Figure 2, the CO2container e is a shallow vessel having a shallow V-shaped bottom fittedwith heat exchange fins c, this container being fitted in a roof spaceand fragments of roof fittings being indicated at r and T The shuttersconsist of a pair of angle plates 0 0 each plate being mounted on a rockshaft 8 at the apex of its angle. In the closed condition of theshutters, illustrated in full lines in Figure 2, each plate part c restsagainst a roof fitting r or r and each plate part c rests against atrough t extending along beneath the container 6 and adapted forcollecting moisture which condenses upon the bottom of the container andruns down to the middle drip point above the trough. The closedcontainer 2 is connected by a pipe g with a valve casing n, the blow-01fvalve f being on the pipe in this case. Admission of gas from the pipe 9to the casing 11 is controlled by a valve 0 which is operativelyconnected with a diaphragm or piston device in a chamber n thelast-named being connected by a tube with the thermostat bulb m. Thevalve casing n is connected by-a pipe with the pressure device It, thediaphragm of the latter being connected by a link 1) with a two-armedlever q. The top arm of the lever q is connected by a link it with thelower arm of a two-armed lever 12, the upper arm of this lever beingconnected with the plate part c of the right hand shutter. The lower armof the lever q is connected by a link u with the lower arm of atwo-armed lever 0 the upper arm of this lever being connected with theplate part c of the left hand shutter. When the temperature influencingthe bulb m rises, the pressure due to expansion of the fluid becomesoperative in the chamber n for opening the valve 0. Thereupon, gas isadmitted to the device It to dilate the diaphragm thereof.

The consequent push on the link 21 causes the three levers q o and v tobe rocked to the dotted line position with the result that the shutters0 .0 are rocked to an open position shown in dotted lines. In this openposition, relatively warm air at the roof can pass over the top edges ofthe shutters to become cooled in contact wit! the CO2 chamber ewhereupon this air descends between the bottom edges of the shutters andthe trough t, as indicated by the dotted arrows in Figure 2.

Figures 3 and 4 show apparatus similar to that of Figure 2 as it appearswhen installed in the roof of a vehicle, and in Figure 3 it will be seenthat the shallow container e may be of considerable length so that itextends along the roof. The container e may be charged with blocks ofCO2 through hand holes in the roof, these being closable gas-tightly bymeans of plugs or covers a: held down by fastening means :0 Figure 4shows the shafts s supported by brackets 1/ from the roof fittings r rand the trough t, which is drained by a pipe t suspended by small plates2 from the CO2 container. It will be clear from Figures 3 and 4 that theshutters c c are co-extensive with the container e along the roof, thepressure device It for operating them being shown to the right-hand sideof Figure 3 together with the linkage through which it opcrates, whichlinkage will be described in detail with reference to Figure 5.

Referring to Figure 5, the left hand shaft s is fitted with an upwardlyextending arm I and the right hand shaft 8 is fitted with a downwardlyextending arm 2, the arms I and 2 being interconnected by a link 3 ofadjustable length. This interconnection ensures simultaneous andopposite turning of the shafts s, as is necessary for producing themovements of the shutters c 0 already described. The right hand shaft shas fixed to it an arm 4 which has a pin and slot connection with oneend of a lever arm 5, the pin being insertable into any one of a numberof holes to provide a rangeof adjustment. The lever arm 5 is pivotallymounted at its opposite end in a hanger 6 suspended from the pressuredevice It, the latter being suspended from the roof by brackets 1. Adisc 8 attached to the diaphragm of the pressure device has a boss atits centre which is connected with the lever arm 5 by means of a dividedscrew threaded rod 9, the parts of the latter being united by a screwthreaded coupling sleeve III which can be turned to adjust the length ofthe rod. Referring to Figures 4 and 5, it willbe apparent that dilationof the diaphragm will depress the rod 9, Figure 5, and the lever arm 5,thereby turning the right hand shaft s counterclockwise and the lefthand shaft 3 clockwise to effect opening of the shutters c c Figure 4.The operation of the similar apparatus in Figure 2 having already beendescribed, further description of the apparatus in Figures 4 to 6 isthought to be unnecessary.

I claim:

1. Refrigerating or V cooling apparatus comprising an evaporativerefrigerant container capable of withstanding pressure, a power elementhaving a diaphragm adapted to be flexed by pressure fluid supplied tosaid element from the container, a pipe connecting said container withsaid power element, a shut-off valve in said pipe,temperature-responsive means operative on said valve for controllingpressure admission to the power element, and a shutter deviceoperatively connected with the diaphragm of said power element forregulating circulation past the container,

2. Refrigerating or cooling apparatus comprising an evaporativerefrigerant container capable of withstanding pressure, a power elementhaving a diaphragm adapted to be flexed by pressure fluid supplied tosaid element from the container, a pipe connecting said container withsaid power element, a shut-oif valve in said pipe,temperature-responsive means operative on said valve for controllingpressure admission to the power element, said pipe being formed with aheat exchange coil, and a shutter device operatively. connected with thediaphragm of the power element for regulating air circulation past thecontainer.

3. Refrigerating or cooling apparatus comprising an evaporativerefrigerant container capable of withstanding pressure, a leaky powerelement having a diaphragm adapted to be flexed by pressure admittedfrom the container, said leak permitting return of the diaphragm tonormal when pressure admission is shut off, a pipe connecting said.container with said power element, a shut-off valve in said pipe,temperature- 2 responsive means connected to operate said valve forcontrolling pressure admission to the power element, and a shutterdevice operatively connected with the diaphragm of the power element forregulating air circulation past the container.

4. Refrigerating or cooling apparatus comprising an evapor'ati'verefrigerant container capable of withstanding pressure, a power elementhaving a diaphragm adapted to be flexed by pressure admitted from thecontainer, a pipe connecting said container with said power element, ashut-off valve in said pipe, temperature-responsive means connected tooperate said valve for controlling pressure admission to the powerelement, a pair of rock shafts, a pair ofangle plates each mounted atthe apex of its angle on one of said rock shafts respectively, saidro'ck shafts and angle plates being operatively connected with thediaphragm of said power element for regulating air circulation past thecontainer.

JOHN FU'RSE BANCROF'I' VIDAL. 20

